Architectures for Cognitive Radio Testbeds and Demonstrators – An Overview

Wireless communication standards are developed at an ever-increasing rate of pace, and significant amounts of effort is put into research for new communication methods and concepts. On the physical layer, such topics include MIMO, cooperative communication, and error control coding, whereas research on the medium access layer includes link control, network topology, and cognitive radio. At the same time, implementations are moving from traditional fixed hardware architectures towards software, allowing more efficient development. Today, field-programmable gate arrays (FPGAs) and regular desktop computers are fast enough to handle complete baseband processing chains, and there are several platforms, both open-source and commercial, providing such solutions. The aims of this paper is to give an overview of five of the available platforms and their characteristics, and compare the features and performance measures of the different systems

Multiple antennas for 4G wireless systems

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Wij blijven mensen! Gedetineerden over de gevangenis van de toekomst

Een gevangenisverpleegster wordt vermoord door een koppel. Tijdens de feiten was de vrouwelijke dader in penitentiair verlof, haar mannelijke mededader voorlopig vrijgelaten. In Luik vallen vier doden na een schietpartij. De dader had net de gevangenis verlaten omwille van penitentiair verlof. Er klinkt felle kritiek op hoe we omgaan met gedetineerden. Maar hoe kijken zij er zelf naar?status: Published onlin

Joint carrier and clock offset compensation in a mobile 802.16e OFDMA communication system

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Energy-efficient communication processors

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A flexible transmission scheme for 4G wireless systems

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Flexible MIMO transmission scheme for 4G wireless systems with multiple antennas

New air interfaces are currently being developed to meet the high requirements of the emerging wireless communication systems. In this context, the combinations of the multicarrier (MC) and spread-spectrum (SS) technologies are promising candidates. In this paper, we propose a generic transmission scheme that allows to instantiate all the combinations of orthogonal frequency-division multiplexing (OFDM) and cyclic-prefixed single-carrier (SC) modulations with direct-sequence code-division multiple access (DS-CDMA). The generic transmission scheme is extended to integrate the space-division multiplexing (SDM) and the orthogonal space-time block coding (STBC). Based on a generalized matrix model, the linear frequency-domain minimum mean square error (MMSE) joint detector is derived. A mode selection strategy for up- and downlink is advised that efficiently trades off the cost of the mobile terminal and the achieved performance of a high-mobility cellular system. It is demonstrated that an adaptive transceiver that supports the proposed communication modes is necessary to track the changing communication conditions.info:eu-repo/semantics/publishe

A generic transmission scheme for fourth generation wireless systems

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